Usage of 40bar = 160 CFM, so 20bar is 80 CFM??

[PrideExhaust]

http://en.wikipedia.org/wiki/Cubic_feet_per_minute

I'm calculating the CFM usage from our high pressure boosters/compressors. If 40 bar of usage is 160 CFM will 20bar of usage is 80 CFM? Thank you in advance.

Mark

[broinkrist]

pressure and flow rate are not linear relationships.

that is why turbochargers and superchargers have compressor maps. it is pretty much entirely derived by experimentation.

[PrideExhaust]

pressure and flow rate are not linear relationships.

that is why turbochargers and superchargers have compressor maps. it is pretty much entirely derived by experimentation.

How do I calculate the 20bar? Any info you need?

[broinkrist]

each specific compressor, whether it be a turbocharger or supercharger, has a specific compressor map. each specific compressor makes power in different locations at different pressures. you need the specific compressor map for the compressor you are looking at and go from there.

what is the application you are looking for? there are plenty of very well researched supercharger and turbocharger options for the nsx platform and they are currently being used in 'kits' like the lovefab setup, angus's setup, the CTSC, the SOS SC, etc...

here is a useful link for reference. they have a bunch of compressor maps to start calculations...
http://www.rbracing-rsr.com/turbotech.html

[Vega$ NSX]

How do I calculate the 20bar? Any info you need?

It's not a simple equation. You would use something like Bernoulli's equation of compressible flow. However, manufacturers of turbos/superchargers have either already calculated these using this equation or have mapped out the relationship using emperical data.